HIV: Pneumocystis Jiroveci Pneumonia

Key points

• Whilst the organism Pneumocystis carinii is now referred to as Pneumocystis jiroveci, the term Pneumocystis carinii pneumonia (PCP) is still in common use
• Pneumocystis jiroveci is an unicellular eukaryote, generally classified as a fungus but some authorities consider it a protozoa
• PCP is the most common opportunistic infection in AIDS
• all patients with a CD4 count < 200/mm³ should receive PCP prophylaxis Features
• very few chest signs
• TREATMENT (BHIVA pulmonary OI guideline 2024): CO-TRIMOXAZOLE (trimethoprim-sulfamethoxazole) is the treatment of choice for PCP of ANY severity · moderate-to-severe disease (PaO₂ < 9.3 kPa at rest on room air) is treated intravenously in hospital, switching to oral to complete the course.
• ADJUNCTIVE CORTICOSTEROIDS (Grade 1A) if PaO₂ < 9.3 kPa, OR SaO₂ ≤ 92% at rest, OR oxygen saturation falling by 3% or more on exercise · give as soon as possible and WITHIN 72 HOURS of starting anti-Pneumocystis therapy — benefit has only been demonstrated within that window. Note the UK threshold is expressed in kPa (9.3), not the US mmHg convention.
• If co-trimoxazole cannot be tolerated: oral primaquine with IV or oral clindamycin for moderate-to-severe or mild-to-moderate disease; atovaquone for mild disease (Grade 2B) · check G6PD status before primaquine.
• Pneumothorax is a common complication of PCP. Extrapulmonary manifestations are rare (1-2% of cases), may cause